isuog basic training · cavum septum pellucidum 3. rugby football shape, rounded at back, more...

Basic Training

ISUOG Basic TrainingDistinguishing between normal and

abnormal fetal anatomy

Basic Training

Learning objectives

At the end of the lecture you will be able to:

• Compare the differences between the ultrasound appearances

of normal fetal anatomy & of the more common structural fetal

abnormalities

• Incorporate all this knowledge into your 20+2 planes scanning

approach to the mid trimester & third trimester scans

• Combine this knowledge with your assessment of the fetal

biometry & of the amniotic fluid

Basic Training

Key questions

1. Which abnormalities can be excluded by obtaining normal

HC/BPD, AC & FL sections in the 2nd or 3rd trimester fetus?

2. What are the principal differences in ultrasound appearances

between a structurally normal fetus and a fetus with one or

more of the more common structural abnormalities ?

Basic Training

Anatomical

area

Plane Description

Overview 1 Sweep 1 Longitudinal head & body for initial orientation

Spine 1

2

3

Sagittal complete spine with skin covering

Coronal complete spine

Coronal section of body

Head 4

5

6

Transventricular plane*

Transthalamic plane*

Transcerebellar plane*

Thorax 7

8

9

10

Lungs, 4 chamber view of heart

Left ventricular outflow tract (LVOT)

Right ventricular outflow tract (RVOT) & crossover of LVOT

3 vessel trachea (3VT) view of heart

The 20 + 2 planes

* measurement required

Basic Training

Anatomical area Plane Description

Overview 1 Sweep 1 longitudinal head & body for initial orientation

Spine 1

2

3

sagittal complete spine with skin covering

coronal complete spine

coronal section of body

Head 4

5

6

transventricular plane*

transthalamic plane*

transcerebellar plane*

Thorax 7

8

9

10

lungs, 4 chamber view of heart

left ventricular outflow tract (LVOT)

right ventricular outflow tract (RVOT) & crossover of LVOT

3 vessel trachea (3VT) view of heart

The 20 + 2 planes

* measurement required

Anatomical area Plane Description

Abdomen 11

12

13

Transverse section of abdomen with stomach & umbilical vein*

Transverse section of abdomen at cord insertion

Transverse section(s) of left kidney & pelvis, right kidney & pelvis

Pelvis 14 Transverse section of pelvis, bladder, both umbilical arteries

Limbs 15

16

17

Femur diaphysis length*

3 bones of both legs, both feet & normal relationships to both legs

3 bones of both arms, both hands & normal relationships to both arms

Face 18

19

20

Coronal view of upper lip, nose & nostrils

Both orbits, both lenses

Median facial profile

Overview 2 Sweep 2 Transverse sweep of body from neck to sacrum, one vertebra at a time

Basic Training

Establishing fetal position & situs (overview 1)

L

Abuhamad & Chaoui. Practical Guide to Fetal Echocardiography: Normal and Abnormal Hearts. 2nd Edition, 1997.

Basic Training

Establishing fetal position & situs (overview 1,2)

Basic Training

When performed correctly the 20 + 2 approach has the potential to exclude 50

abnormal fetal appearances:

Exclusion of structural abnormalities

Plane Anatomical area Abnormal appearances

Sweep 1 1

1-3 Spine 6

4-6 Head 8

7-10 Thorax 16

11-13 Abdomen 8

14 Pelvis 3

15-17 Limbs 3

18-20 Face 5

Sweep 2 all all

TOTAL 50

Basic Training

20 + 2 planes & abnormal appearancesPlane Area Abnormal appearances {50+intrauterine death (IUD)} excluded by the correct 20+2 approach

Sweep 1 Anencephaly, Intrauterine death

1-3 Spine Abnormal abdominal situs, left sided diaphragmatic hernia, meningocoele,

Open spina bifida, sacral agenesis, sacral coccygeal teratoma,

4-6 Head Alobar holoprosencephaly, banana shaped cerebellum, cystic hygroma, large posterior fossa cyst,

lemon shaped skull, occipital encephalocoele, skin oedema, ventriculomegaly

7-10 Thorax atrioventricular septal defect (AVSD), congenital pulmonary airway malformation (CPAM), double aortic

arch, ectopia cordis, overriding aorta, persistent left vena cava*, right aortic arch, severe aortic

stenosis, coarctation & pulmonary stenosis, significant pericardial effusion (>4 mm) & pleural effusion

(>4 mm), situs inversus/ambiguous, tetralogy of Fallot, transposition, univentricular heart, ventricular

septal defect (VSD) (moderate/large)

11-13 Abdomen Ascites, bilateral renal agenesis, duodenal atresia, echogenic bowel*, gastroschisis, omphalocoele,

renal pelvic dilatation (>7 mm anterior posterior/AP), small/absent stomach

14 Pelvis Cystic renal dysplasia, lower urinary tract obstruction, 2 vessel cord

15-17 Limbs Fixed flexion deformities wrist, severe skeletal dysplasia (some), talipes

18-20 Face Anopthalmia, cataract*, cleft lip, proboscis*, severe micrognathia

* optional, for local decision as to whether or not included

Basic Training

1. Midline (falx cerebri)

2. Cavum septum pellucidum

3. Rugby football shape, rounded

at back, more pointed at front

4. Skull contour regular

5. Atrium of lateral ventricle <10 mm

6. Anterior horn(s) slit-likeCSP

T

T

Falx Lateral

Ventricle

3V

*

Key features of HC section: plane 4

(transventricular)

Plane 4

Basic Training

*

Cerebellum

T

T

Falx

Key features of plane 6 (posterior fossa)

Plane 6

Basic Training

NTD - abnormal appearances of plane 4 (transventricular),

5 (transthalamic)

Ventriculomegaly

Ventriculomegaly

with lemon/ shaped skull

Anencephaly 20w

Normal plane 4

Normal plane 5

Basic Training

20 + 2 planes & abnormal appearances

Plane Area Abnormal appearances (50+IUD) excluded by the correct 20+2 approach






7-10 Thorax AVSD, CPAM, double aortic arch, ectopia cordis, overriding aorta, persistent left vena cava*, right aortic

arch, severe aortic stenosis, coarctation & pulmonary stenosis, significant pericardial effusion (>4 mm)

& pleural effusion (>4 mm), situs inversus/ambiguous, tetralogy of Fallot, transposition, univentricular

heart, VSD (moderate/large)


renal pelvic dilatation (>7 mm AP), small/absent stomach





Basic Training

Plane 4 Plane 2Plane 1

Abnormal appearances

NTD - abnormal appearances: planes 1 (sagittal spine), 2 (coronal spine),

4 (transventricular), & 6 (transcerebellar)

* *

Plane 1 Plane 2Plane 4 Plane 6

Plane 6

Normal appearances

Basic Training

20 + 2 planes & abnormal appearancesPlane Area Abnormal appearances (50+IUD) excluded by the correct 20+2 approach











renal pelvic dilatation (>7 AP), small/absent stomach





Basic Training

R

L

• Sits to the left of the chest

• Area 1/3 chest

• Circumference ½ chest

• Aorta is just anterior to the spine and

to the left

Abuhamad & Chaoui. A Practical Guide to Fetal Echocardiography: Normal and Abnormal Hearts. 3rd Edition, 1997.

Normal appearance of plane 4

(lungs & 4 chamber view)

Plane 7

Basic Training

Normal appearance of plane 4


• Right ventricle is the most anterior, below the

sternum

• Left atrium is closest to the spine and the

most central structure in the chest

• Tricuspid valve is more apical than the mitral

valve

• Flap of the foramen ovale is in the left atrium

• Moderator band is in the right ventricle

• Crux seen

RL

Sp

DAo

Plane 7

Basic Training

Plane 7

Plane 11

Plane 7

Plane 7

Plane 7

Abnormal appearances of plane 4


Basic Training

20 + 2 planes & abnormal appearances

Plane Area Abnormal appearances (50+IUD) excluded by the correct 20+2 approach
















Basic Training

1. Short length of umbilical vein,

opposite spine

2. Single stomach ‘bubble’, on left side

3. Remaining echotexture homogeneous

4. Gall bladder to right of umbilical vein (UV)

DAoS

SpUV

*

*

Key features of AC section

plane 11 (abdomen)

Plane 11

Basic Training

Measure AC

Plane 11

Basic Training

Abnormal appearances of plane 11 (abdomen)

Plane 11

*

*

Plane 11

Plane 11

Basic Training

Plane 12

1. Slide inferiorly from AC to

sacrum

2. Maintain cross sectional

approach

3. Cord inserts superior to

bladder

Normal appearances of plane 12 (cord insertion)

Plane 12

Basic Training

Abnormal appearances of plane 12 (cord insertion)

Abdominal wall defects

Omphalocele – abnormal cord insertion

• Cord inserts into apex of defect

• Contains liver +/- bowel etc

• Membrane covered

Gastroschisis – normal cord insertion

• Defect below & to right of cord insertion

• Contains bowel only

• Free floating

Plane 12

Plane 12

Plane 12

Basic Training

Kidneys

• Lateral to spine

• Posterior to stomach

• Normal renal tissue similar echogenicity

to bowel, liver etc

• Coronal view allows easier comparison

• Cortex homogenous echopattern

• Renal pelvis, centrally positioned,

<7.0mm AP

Plane 13

Plane 3

Sp

Normal appearances of plane 13 (transverse kidneys) and 3

(coronal body)

Basic Training

















Basic Training

Normal appearance of plane 14 (bladder)

Bladder

• Central position in fetal pelvis

• Thin walled

• No internal content

• Size varies (~30 minute cycle)

• Umbilical artery on each side

Plane 14

Plane 14 Plane 14

Basic Training

Urinary tract obstruction – abnormal appearances of planes 13

(transverse kidneys) & 14(transverse bladder)

Plane 13

Plane 13

Plane 13

Plane 14

**

Plane 14

Sweep 1

*

*

Plane 13

*

*

*

Sweep 1

Basic Training

















Basic Training

Key features of FL section: plane 15 (femur)

• Both ends of ossified metaphysis clearly visible (rotate + slide)

• Distal femoral epiphysis if visible or spur artefacts should not be included

• Angle of femur to incident beam should correspond to technique of reference chart (dip)

• Recommend 00-150 to horizontal

http://fetalanomaly.screening.nhs.uk/standardsandpolicy

Plane 15

Basic Training

Planes 16 (lower limbs) & 17(upper limbs)

• Number of bones

• Length, FL + visual assessment

• Echogenicity

• Shape

• Position (hands & feet)

• Movements, flexion, extension

Plane 16

Plane 17

Basic Training

Normal & abnormal appearances of planes 15

(femur) -16 (lower limbs)

Plane 16

Plane 15Plane 16Plane 15

*

*Sweep 1

Basic Training

















Basic Training

Planes 18 (upper lip), 19 (orbits), & 20 (profile)

Plane 18

Plane 19

Plane 20

Plane 18

Plane 19

Plane 20

*

*

Basic Training

Size and relative size

Small HC (below 5th centile)

• Microcephaly

• Spina bifida

Small FL (below 5th centile)

• Skeletal dysplasia

• Down’s syndrome

• Early FGR ?

Small AC (below 5th centile)• Congenital diaphragmatic hernia

(CDH)

• Abdominal wall defect

• Early fetal growth restriction (FGR)

Plane 4 Plane 11 Plane 15

Basic Training

Amniotic fluid volume

Polyhydramnios

• Anencephaly

• Upper gastrointestinal tract (GIT) anomalies

• Skeletal dysplasias involving small chest

Oligohydramnios / anhydramnios

• Renal anomalies

• Fetal growth restriction

• Premature rupture of membranes

DVP 2-8 cm

AFI 5-24 cm

Basic Training

Normal or abnormal appearances? (planes 1-20, sweeps 1 & 2)

Basic Training

Key points

1. The key to identifying abnormalities is understanding the range of

normal appearances at differing gestations

2. It is important to develop a consistent & logical approach to each

scan, rather than scanning randomly. The 20+2 planes approach

provides this consistent & logical approach

3. If you are unable to confirm that the appearance and/or size of the

fetus is normal, seek a more experienced opinion

Editable text hereBASIC TRAININGBasic Training

ISUOG Basic Training by ISUOG is licensed under a Creative Commons Attribution-NonCommercial-

NoDerivatives 4.0 International License.

Based on a work at https://www.isuog.org/education/basic-training.html.

Permissions beyond the scope of this license may be available at https://www.isuog.org/

https://www.isuog.org/education/basic-training/basic-training-online-module.html

http://creativecommons.org/licenses/by-nc-nd/4.0/

https://www.isuog.org/education/basic-training.html

https://www.isuog.org/

isuog basic training · cavum septum pellucidum 3. rugby football shape, rounded at back, more...

Documents